O-26 Occupational differences in risk of COVID-19: findings and methodological issues

Introduction

It is well-established that certain occupations that have frequent contact with patients (e.g. health care workers) or the public (e.g. bus drivers), may have increased risks of Covid-19. However, estimating these risks involves a number of important methodological problems. Not everyone who has a SARS-CoV-2 infection gets symptoms; not everyone with symptoms gets tested; not all tests yield valid results.

Methods

Therefore, a variety of approaches are necessary for obtaoning valid estimates of the (relative) risks of Covid-19 in various occupational groups. These include: (i) linkage with census data to adjust for non-workplace factors; (ii) test-negative design studies of Covid-19 infection; (iii) excess mortality analyses; and (iv) proportional mortality analyses.

Results

Some occupations such as health care and social care workers have consistently increased risks of Covid-19 infection and mortality. Other occupations have markedly different results depending on the method of analysis used.

Conclusions

These methodological issues are not insurmountable, but require careful study design and data analysis. In particular: (i) when not everyone is being tested, then comparisons between and within occupations can be biased, but this bias can be minimised using the test-negative design; and (ii) comparisons between occupations require careful and rigorous adjustment for work-related ‘living conditions’.